Ito model



No. 752,667. PATENTBD PEB. .23. 1904.,

H. GRUBE. GEODBTIGAL INSTRUMENT.

APPLICATION FILED SEPT. 21, 1901.

No MoDEL. SHEETS-SHEET 1.

No. 752,667. l .PATENTBD FEB'. 23, 1904. H. GRUBB. GEODETIGALINSTRUMENT.

APPLmATxoN FILED s221221, 1901. No MODEL.

' 3 SHEETS-SHEET 2.

No. 752,667. Y PATBNTED PBB.23, 1904.

H. GRUBB.

GBODETIUAL INSTRUMENT.

I APPLIOATION FILED SEPT. 2l, 1901.

N0 LMODEL. 3 SHEETS-SHEET 3.

-lilit'irizn @trarne Patented February e3, 1904.

Partnr Unsinn.

HOM/'ARD GRUB, FDUBLIN, IRELAND.

esoos'reom. 'waarnemen-'s'.

SPECSIFICATXGN forming part of LettersPatent No. 752,667, dated February23, 1904. Anuman ned sommier 21,1961. soi-inno. 76,115. (Nomade.)

l to he sighted vand au image of an object carried hy the sightingdevice and constituting the sight proper can be superposed or caused tocoincide in such a way that they can he seen sinuiltancousljyY and thatthe sight shall apnear'to be approximately as far distant as the objectbeing' sighted, so that it can be viewed under practically the saineoptica-l ,conh

ditions as the object, the result being that the sighting et the distantobject can be eiiected with greater ease, comfort, and accuracyT thanpossible with any et' the. ordinary arrangements olI nalied-cyesightsgin using which itis impossible to focus the eye. sinuiltaneouslir on the-l'ore sight and the object and in which also there is a large parallax,`which necessitates the use of a bachv sight to help the observer topreserve the i'lecessary lixity et position of the eyeduring-ebservation For produc an image ci' the sight .such as referredto there are used, in conjunction With a sight formed, for example, bythe image of a line, cross, or other device formed by one or more slitsor transiiiarent lines in or on an opaque diaphragm, means whereby theluminous rays proceeding` therefrom te the' eye of an observer arerendered either by retraction or by reflection parallel to oneanother'z'md a refiecting-suriace frein which an image of the sight canbe retlected'and caused to enter thecye ot' the observer simultaneouslywith view et" a distant object. The reiiecting-surfacemay be that ofplain glass; butin order to increase the brillianey and cles-mess of theiniageof the Sight reflected therefrom it is preferred to use atransparent body, coated with a film et' a redecting medium, such assultid of lead or metallic silver, that will increase thereiicetingnewer of the reflecting-surface oi the l transparent body,while allowing oi the passage of rays of lig-ht therethrough.

New the present invention has reference to the construction, withsighting devices and transparent reiiecting-tihns of the kind referre'dto, of geodetical instruments of various kinds-suce for example, asprismatic compasses, inelinometers, graphometers, and levels-wherebywithout appreciable addiproduced which offer facilities for obtainingmore accurate results than have been usual with instruments asheretofore used, besides strunients by persons not specially skilled intheir use.

. The invention consists in various novel features of construction andcombinations and arrangementsof` parts, all as hereinafter described andafterward more particularly pointed out in the claims. I

in the accompanying drawings, Figure l is a plan, ,and'lig 2 a sectionon the Aline A A et' Fig". l, show ing one construction of geodeticalinstruments according to this invention. Fig. 2 is a horizontal sectionon the line A' A' oi' Fig. 2. Fig. 2h is aview of a diaphragm withmodifiedsight for use in the instrument shown in Figs. 1, 2, and 2,Figs. 3 to 7, inelusive, show a geodetical instrument according to thisinvention suitable for use at will either as a prismatic compass or asan inelinometer, or as a graphometer ocplane table,` or as a level, Fig.3 being a section on the line B B et'. Fig. 4; Fig. 4, a sectional planon the line C C et' Fig. 3; Figs. 5 and 6, vertical sections on the lineD D. and E E, respectively, of Fig'. 4; and Fig. 7, a view of the outerend of the collimator-tube. Fig. 6'? is a similar view to Figi (5showingthe instrument adapt` ed* for use as aninclinoineter.f` Fig. 8isa as a grapherneter.l

shown in' Figs. l and 2Y the sighting device @,rupon the top of whichand over a hele therein the compass-card hox'oisixed, is of thereiiecting type. lt comprisesa tube that In theconstruction of prismaticcompass tional cost instruments such as referred to are alsofacilitating the employment ot' such ini -vertical section, and Fig. 9anlan showing a modified form of apparatus adapted forfuse is providedat its forward end with a comparatively large opening (l, closed by apiece of transparent glass e, that has a .concave inner surface coatedwith a transparent reflecting-hlm of the hind her inbefore referred toand through which a distant object can be seen by an observer lookingthrough the rear end of the tube, which is provided with an eyepiece oropening f for the purpose. At the side of the front opening (l is anarrow einnpartment ,7, the front end of which is of opaque material,formed with a very narrow i or thin vertical slit 7l, to constitute asight through which luminous rays can pass in a backward directionthrough the open rear end ot the compartment g and fall upon arefiecting-surface c, so inclined or arranged at the back of the tube,as shown, as to reflect them in a 'forward direction and cause them tofall upon the concave reflecting-surface ot' the piece of e at the frontof i-tlie tube (1 from which surface the luminous rays torman image ofthe line or sight are reflected in backward directionand parallel to oneanother to the rear eyepiece or opening f. The reliect'ing-surface f maybe formed by a reflecting-(lim of chemically-deposited silver upon apiece oi parallel glass, through which image of the sight and thedistant object can be seen. Behind the slit /t Imay be an opaquediaphragm---ioin example, oi glass, coated with silver, paint, or thelilie--through which is cut a thin vert-ical line to constitute lthesight, as in the construction of instrument shown in Figs. 3 to 7,inclusive, and hereinafter described, Such a diaphragm is shown indotted lines at 71,' in Fig. 2'. lf, however, the slit Il, be made verythin and straight, the additional diaphragm can in some cases be dispenscd' with.

Below the hole in the bottom of the compass-card box c and the top et'the sightingtube o is an inclined reflecting plane su rface m, formed,for example, by an inclined mii'- ror, shown, or by the silver-edinclined Surface'oi' a riglit-angle(.l prism so arranged that an imageof thc particular division of the ein cular .row of angular divisions non the compass-card n, which gives the bearing of the object beingobserved, will be reflected backward through the rear eyepiece oropening f, the ghost or image of the vertical line of' sight 7i, whichserves for sighting the object, also serving as a nonius or index forreading the Vsaid division on the compass-card.

ln the example the inclined reflecting-surface my blocks out a smallportion of the upper part ot the vertical line constituting the sightbut allows a portion of the compass-- card n to be seen instead, and asthe compasscard is arranged at about the same distance` above thereflecting-surface fm, the vertical slit 1i. isibehind it and both areat a distance from. the concave mirror equal to its focal length theluminous rays entering the eye ot' an o5;

observer from both the divisions on the coinpass-card and from thevertical slit are perfectly parallel. Consequently there is no parallaxbetween them or between either oi them and the distant object whosebearing it is desired to obtain.

rlhe compass-card box c is removably attached to the upper side of thesightingtube a, as by a dovetailed-shaped projection c on the 4oneengaging a corres]iondingly-shaied groove or recess c2 in the other, sothat the compass-card box can be readily removed and replaced by a boxcontaining a clinometer and made like the compass-box, with an openingin its bottom corresponding to the opening l in the sighting device. Bythen turning the instrument side wise through an angle or' ninetydegrees it can be used as an inclinometer for obtaining the bearings ofobjects in a vertical plane, the .mode of using the instrument being thesame as with the prismatic compass; but the image ot the sight insteadof being a vertical line-will then be a horizontal one.

Fig, 6" showsthc instrument provided with an inclinometer and arrangedfor nieasurinf.:l

vertical angles. to the compass, except that the graduated conipass-cardin, and magnetic needle used in that instrument are replaced by apivoted ring, disk, or carrier M, which is weighted at its lower side,asfby a weight M, and .is provided with a graduated transparent oropaque scale of degrees on an opaque or transparent annular strip M2,the arrangement being such that when in use the'weighted ring, wheel, orcarH rier M, with strip M2, will be held stationary lhe inclinomcter issimilar.

by gravity, whilethe'box C, in which the said Y parts are pivot-ed', ispartly rotated with the sighting device to which it is attached, tin-yrear wall oi the box having an `openiifig l therethrough opposite thestrip l 2 and also a dovetailed-sliaped projection U, by which it can bedetaehably connected to the sightingtube It. l

In the instrument shown in Figsy 8 to '7, inclusive, the sighting deviceis shown as ol the refracting type, the sighting-tube r1, being closedat the front and rear ends with pieces. u and 0, respectivi'ily, ofplane glass and pro-- vided at an intermediate part with a piece y ofparallel glass arranged at an angle ot fortylive dcgrees'to thelongitudinal ot ther tube, one of the surfaces of the piece oi' parallelglass being provided with a reflectingiilm ol. the kind hereinbeforereferred to. The collimator-tube y is arranged at right angles to thesighting-tube o and is provided at its outer end with a' diaphragm li',carrying thesight li, and at its inner end with an achromatic lens orobject-glass 1], whereby the luminoua rays proceeding from the sight iare rendered parallel before impinging upon the inclinedreflecting-surface of the piece 7i IOCl . desired.

of parallel glass. The diaphragm fr `may be made removable, so thateither a diaphragm ifiearing a sight la in the forni of a single tineline or a diaphragm bearing a sight in the.

form of a scale, as in Fig. i', may be used, as The top of thecoliirnator-tubc f/ is ad; )ted to carry the removable box c ot' theprismatic compass or the inclinometer and is iu'ovided with the hole 71and inclined mirror fm, by which an ima-ge ofthe divisions on the'portion of the card n. of the compass or inclinomcter just above thehole will he reiiccted onto the inclined piece j) of parallel lglass.simultaneously with the image ot the sight it and viewed while sightingthe, object Whose position is to he noted.4

The ,under side of the sighting device is provided at the front end witha needle-points to serve as a pivot and at the rear end with a springneedle-point t, and to the front end of the `said device is pivotedi anarm fu, provided with a needle-nein te. The three needlei points .5" tand the vertical image of the line representing` the sight /t arearranged to come in the saine vertlcal plane. 1

'ifo the under side of the instrument 1s fixed `a water or spiritV levelfw, and to enable the aiwbubble thereoil to heviewed simultaneously withthe sighting of a surveyors staff at a distance the radius arm a isprovided with a mirror fu, in' which when the arm' is folded under theinstrument an image of theair-hubbie can be viewed while sighting the.surveyoris staff. l Y

The compound instrument can be used in the manner hereinhefore describedas a prismatie cmpass or as an inclinometer, a compass-card boav or anincllnometer-hox being attached to the tcp of the sighting.;` device, as

' tutore employedin gr A survey can be made with this instrument.

required, and a diaphragm it' used hearing a sight in the form of aiinestraight line. VAit this time the pivoted arm u is folded under thesighting-tube (t.

' iii/hen the instrument isto -be used as a graphometer, it is pivotedby. means of its needle-point s to av table `or hoard above a l sheet ofpaper upon which a survey` is to he made. The instrument can then bemoved about its pivot s, so as to bring the image of the sight l1. on adistant object, such as a stad, held at diiierentparts of the ground tobe surveyed and each corresponding position of the instrument indicatingthe bearing otv the obj'eetv'ateach position can he noted on the paperby depressing Vthe spring needle-points t and n. By this arrangementmuch 'greater accuracy can he obtained/than with the sight-i viz. a slitjdd cross-threads herephometers. l

ing device by mounting it 4to turn on a drawing-hoard at oneobservation-station and pricking off on the 'paper the hearings of thevarious `points to be noted, as indicated hy astat `or vconsiderableaccuracy.

that the distances of the various points can he at once estimated bynoting` the apparent size of an object ci humm-height with the aidot'the image of the scale which isthrown on the object, the distance being;recorded on the paper adjacent to the bearings of the correspending`points. This method can be carried outvery rapidly and is suitable wheregreat accuracy is not required and time is limited. iVith distances ofnot more than two hundred feet the error need not exceed three per cent.when working' with the unaided eyc or one per cent. when working withthe aid'of alow-power field-glass.

Then the instrument is to be used as a level,

the arm u is folded Vunderneath the tubo (i, the compass or inclinometerremovechand the instrument turned upside down, and either held. in thehand ior rough estimation or attached to parallel plates onatripod-stand, as

in an ordinary geodetical level, 'the diaphragm IL., with. scale-sightniig. 7, being replaced,

by a diaphragm bearing' a sight in the form oi' a simple horizontal lineora cross.

The rear end oi the sighting-tuberi may he provided with a pivotedmirrory, (see Fig. 3,) by means ot' which .the distant eine and.

image of the sight can be Seen by looking down on the instrument insteadoi'jthrough it. Also the outer end of the coliimator-tnbe f/ may beprovided with a mirror e (see Fig. 5) to illuminate the sight it.

1f desired, a combined instrument for use as a prismatie compass,inclinometer, graphometer, and level. maybe constructed with a sightingdevice of the redecting type shown in Figs. 1 and 2. i For this purposethe sighting device shown in Figs. l and 2 may,T be

`provided with a pivots, radius-anna, needle- Vpoints t and Qi, andlevel w, as indicated in dotted lines. Such sighting,` devices ma.)Talso he providedwith a diaphragm bearimgaJ sight in the `form' of ascale, as shownin. Fig. 2". In the modified construction shown in F IOOIIC

8 and 9 the sighting-tube a and collimating-- tube 5] are arrangedon'eahove4 the other, with,

their axes at right angles to one another, and

.are carried by abase 1, that may conveniently b e of triangular shape,as shown, and is adaptedto be pivoted, as by a perforated lug 2 at onercorner and pnl. to a drawing-board above a sheet of drawinglpaper. Thediaing to the numbers that are seen on the sight-- scale. For surveyinga field or other arca the instrun'ient is pivoted by its lugl 2 above asheet ot' drawing-paper and to a drawingboard supported on atripod-stand.arranged at the central portion of the said lield r otherarea, and an assistant, carrying a stall' on which a length of, say, twoyards is distinctly mai-lied, is sent out with instructions to stop atevery corner or wherever the boundary alters its direction and hold thestati" vertical at each ot' such points. then sighted atcach oi suchpoints and brought into the line oi' collimation by turning the wholeinstrument, `including Iits triangular hase 1, about the center of thelug 2, and the length oi' the two yards marked on the stati' is noted.in the number of divisions-occupied in the luminous scale I, projectedonto the marked part `oi the staii. A mark is then made on thedrawing-paper opposite to the corresponding division on the scale 3marked on the side of the triangular base 1, and such niark gives thedirection and distance oi that point et' the survey. ln this way theopera tion et' surveying is 'reduced to a very simple one and avoids anynecessity for the translation ot the value of the divisions. Theinstrument also has the further great advantage that it can be made verycheaply..

'lhe instrumenthereinbeforedescribed with ri'lierence to Figs. 1 to 2",inclusive, may also be provided. as shown in Fig. 2, with a scale 3, asand for the vpurpose above described.

As will he evident, various other changes an be made in thc details ofconstruction of my gcoditical instruments without departing from thespirit and scope of the invention so long as the relative arrangement ofparts shown in the -zlrawings or the mode of operation described in thespecilication is preserved.

'l`he sighting device iii each of the arrange ments hereiiibet'oredescribed may when dcsired be litted with a monocle binocular orytelescope, according to the class oi' instrument, in order to magnifythe apparent size of the object and image, which, being practically atthe same distance, can be seen distinctly with the same focusing of thetelescope or equiva lent. 'l`he accuracy of sightingdoes not, however,depend on the permanence of the position oi the telescope, which-maybeheld in the hand, il' desired.

What l claim'is-` l. ln a gcodetical instrunmnt, the combination withthe geodctical instrument proper, oi a sight and means for renderingluminous rays The staff isproeeeding'thereirom parallel to one anotherand producing a virtual image of the sight that can be projected on theobject being viewed and observed simultaneously therewith While theinstrument is being used to make a meas urement. I

2. A geodetical instrument comprising a. casingt'ormed with an aperturetherein and through which a distan t object can be observed,

a sightmeans for rendering luminous rays proceeding from said sightparallel to one anotherfand for reflecting them backward to the eye ofan observer and producing a virtual image of said sight vthat can beseen simul taneously with a View ot' the distant object, a pivotedcarrier bearing graduations arranged to come opposite the aperture insaid casing, and reflecting means arranged to: relect an image of thegraduations' that are opposite said-aperture backwardvto the eye of anobserver simultaneously with an image of the sight. e

3. A geodetical' instrument comprising a sighting device consisting ot acasing having an aperture therein and through which a distant object canbe seen, a sight carried by said l casing, and means for renderin gluminous rays proceeding from said sight parallebto oneanother andproducing a virtual image oi the sight that can be seen simultaneouslywith the distant object, a box attached to said casing and 'formed withan aperture opposite the apertiire in said casing, a carrier pivotedwithin vsaid box and bearing a circular scale of degrees arranged tocome opposite said apertures, and reflecting means arranged within saidcasing and adapted to produce an image of the portion of the scaleopposite said apertures and enable said image to be seen while viewingthe image of the sight and a distant object, substantially as described.

4. In a geodetical instrument, a sighting device comprisinga'sighting-tube having a piece oi concave-convex across its forward endandan inclined reflector at its rearward end, and a collimating-tubearranged at one side of said sighting-tube and provided with a sight,said piece of concave-convex glass, inclined reflector and sight beingarranged so that luminous rays proceeding from said sight will bereflected by said inclined reflector onto the concave side of the pieceot' concavo-convex glass from which they will be reflected as parallelrays, substantially as described.

5. A geodetical instrument comprising a easing through whicha distantobgeet can be viewed, a sight carried by said casing, meansA forrendering luminous rays proceeding ytrom at the under side of sai'dcasing,andvsr5 ,"5 "ly IOO movable needle-points located at i the irontand rear of said instrument, said pivot and neeclli1,points being'arranged in thesame vertieal plane as the virtual image oi the sight,sulistantially as described for the purpose specified. i

6. A geodetieal easing through which aldistant object can be viewed, asight carried by said. casing, means Jfor rendering lu minousraysproccedinu' troni said sight parallel to one anothe and forreflecting them bach to the eve of an observer and producing` a virtualiniageolf the sight that can be projected upon the distant object andViewed simultaneously therewith, a level fixed to said easing, andreflecting means whereby an image ot the air-l'iubble or' said level canbe viewed at the saine time as the virtual innige o't said sightandthedistant object. .7. A- ,geodetical instrument comprisinga easingthrough which a distant object can be viewed, a diaphragm carried bysaid casing and bearing a sight in the forni ot a scalo, and means torrendering luminous rays proceeding from said sight parallel and for remfleeting them backward to the eye et' an observer while observing adistant object.

8. `A gcodetieal instrument con'iprising' acasing through which adistant object can be viewed and which is adapted to be turned about avertical center, a diaphragm carried by said casingand bearing a sightin the form ot a scale, and meansfor renderingluminous proceeding fromsaid sight parallel and for reflecting them backward to the eye of auobserver while observing a distant object.

9. A geodetical instrument comprising a casing through which a distantobject can be viewed, a diaphragm carried by said casing' and bearing asight in the lorrn of a calibrated scale, means for rendering luminousrays pro? eeeding' from said sight parallel and for reiiectinc,r thembackward to the eye of an observer,

a pivot at the under side of said casing, and

vertical1jr-movable needle-points located at the front and rear or' saidinstrument, said pivot and needle-points being' arranged in the sainevertical plane as the virtual image ot' the sight7 substantiallydescribed for the purposedcscribed. l v

l0. A geodetical instrument comprising' a casing' through which adistant object can be viewed, a sight carried by said casing' means forrendering luminous rays proceeding from said sight parallel to oneanother and for refleeting them back to the eye of an observer andproducing a virtual image of the sight that can beprojeeted upon thedistant object and viewed simultaneously therewith, a radial extensionhinged or pivoted to the forward end of said casing' and capable ofbeing' iolded under the same, a pivot located at the under side of saidcasini,r and at the forward end thereof, a vertical'lvinovableYneedleqioint'at instrument comprisingr pointe being` arranged in` the`same vertical plane as the Virtual image of said sight.

il. A gcodetical instrument comprising casingthrough which a distantobject can-be viewed, a sight carried by said casing, means YForrendering luminous rays proceeding from. said sight parallel to oneanother and for re ilectine' theinbachY to the eve or' an observer andproducing' a virtual image et the sight that can be projected upon thedistant object and viewed simullnineousljvV therewith, a lerei securedto the under side of said easing, a ra dios-arm hinged or `pivoted tosaid casing and capable of being folded underthe same adjacent to saidleveh and a mirror secured to the under -side oi said radius-arm7substantially described for the purpose speeilied.

l2. ln a geodctieal instrument, a sighting' device comprising' asighting-tube fr having a piece of 'concave-convex glass at its frontendand an inclined piece of parallel glass, at its rear end, the concaveside of said piece ot' concave-convex glass being provided with ascmitransparant reflecting-film and said inclined piece of glass beingprovided with a re fleeting-surface, and a eollimatingiube y er1--tending'trom and inclined to one side ot' said sighting-tube' andprovided at its forward ond with a diaphragm bearing' a sight, substantially described. v

'13. A gcodetical instrument comprising' a sighting-tribe@ piece oiglass extending' across the saine and provided with a semitransparentvreflecting-surface arranged to reflect in a. backward direction,luminous ravs falling thereon, a collimating-tube airing'ed at one sideot' said sightirig-tubet t' `ned with an an# erture through its walland'provided with a diaphragm bearing;n sight, an inclined reflectdevice located behind said aperture, and reflecting' meantfadapted toreilect luminous rays proceeding` from said inclined reflection dev iceand from said sight onto the reflecting surt'ace ot the piece oi glassexttnidingaeross said sighting-tube, and an anglwmcasnrin'g' devicecomprising; a box attached to said rol liniating'tube and torniedwith anaperture in its bottom arranged to coincido with that in saidcollimatingtube, and 'acarrier pivoted in said box and bearing acircular scale of deg'rees extending across said apertures, substantially as described for the purpose specified. f

14C. A gcodetical instrun'ient comprising' a sighting-tube c having atits forward end a piece of concave-convex glass c provided with aseinitransparent retinoting-surface, and atlits rearward ond an inclinedpiece of parallel glass provided with a. reflectiiig-surface, a cobliniating-tube r/ extending' from and inclined to one side ot' saidsighting-tubeand provided l'OO with an aperture b in its top and adiaphragm at the forward end bearing a sight line or lines, an inwardlyand backWa-rdly inclined reiieeting-surface m located at'the inner sideof said aperture, ay box c attached to the combined sighting andeollimnting tubes and formed with an aperture in its bottom Coincidingwith said aperture 7) in the collimatingtube, and a circular carrier 'npivoted Within said box and bearing a Circular scale n of degreesextending over said apertures, substantially as described for thepurpose spceilied.

15. A geodetieal instrument comprising a sighting-tube provide-d with areeetingsurface adapted to reflect, in a backward direction,luminonsrays 'Falling upon it and through which a distant object can be seen, acollimating-t'ube carrying a diaphragm provided with a sight in the formof a scale, means for rendering luminous rays proceeding from said sightparallel to one' another, and for direct ing them ontosaidreflecting-suraee, and e base-piece on which said tubes are mounted,said bese-piece being adapted to turn about vertical center and beingprovided along one side with a scale of distances.

Signed at Rathminos, Dublin, this 3d day September, 1901.

HOWARD GRUBB.

W'itnesses:

EDMUND DooLAN, ROMNEY R. GRUBB.

